Integrated control for silicon photonics

ABSTRACT

In an example, the present invention includes an integrated system on chip device. The device is configured on a single silicon substrate member. The device has a data input/output interface provided on the substrate member. The device has an input/output block provided on the substrate member and coupled to the data input/output interface. The device has a signal processing block provided on the substrate member and coupled to the input/output block. The device has a driver module provided on the substrate member and coupled to the signal processing block. In an example, the device has a driver interface provided on the substrate member and coupled to the driver module and configured to be coupled to a silicon photonics device. The device also has an interface configured to communicate between the silicon photonics device and the control block.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.61/847,523, filed Jul. 17, 2013, and also claims priority to U.S.Provisional Application No. 61/873,784, filed Sep. 4, 2013, commonlyassigned and incorporated by reference herein for all purposes.

BACKGROUND OF THE INVENTION

The present invention relates to telecommunication techniques. Moreparticularly, the present invention provides an integrated electricaloptics multiple chip module and methods.

Over the last few decades, the use of communication networks exploded.In the early days Internet, popular applications were limited to emails,bulletin board, and mostly informational and text-based web pagesurfing, and the amount of data transferred was usually relativelysmall. Today, Internet and mobile applications demand a huge amount ofbandwidth for transferring photo, video, music, and other multimediafiles. For example, a social network like Facebook processes more than500 TB of data daily. With such high demands on data and data transfer,existing data communication systems need to be improved to address theseneeds.

Over the past, there have been many types of communication systems andmethods. Unfortunately, they have been inadequate for variousapplications. Therefore, improved communication systems and methods aredesired.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to telecommunication techniques. Morespecifically, various embodiments of the present invention provide acommunication interface that is configured to transfer data at highbandwidth over optical communication networks. In certain embodiments,the communication interface is used by various devices, such as spineswitches and leaf switches, within a spine-leaf network architecture,which allows large amount of data to be shared among servers.

In modern electrical interconnect systems, high-speed serial links havereplaced parallel data buses, and serial link speed is rapidlyincreasing due to the evolution of CMOS technology. Internet bandwidthdoubles almost every two years following Moore's Law. But Moore's Law iscoming to an end in the next decade. Standard CMOS silicon transistorswill stop scaling around 5 nm. And the internet bandwidth increasing dueto process scaling will plateau. But Internet and mobile applicationscontinuously demand a huge amount of bandwidth for transferring photo,video, music, and other multimedia files. This disclosure describestechniques and methods to improve the communication bandwidth beyondMoore's law.

Serial link performance is limited by the channel electrical bandwidthand the electronic components. In order to resolve the inter-symbolinterference (ISI) problems caused by bandwidth limitations, we need tobring all electrical components as close as possible to reduce thedistance or channel length among them. Stacking chips into so-called 3-DICs promises a one-time boost in their capabilities, but it's veryexpensive. Another way to achieve this goal in this disclosure is to usemultiple chip module technology.

In an example, an alternative method to increase the bandwidth is tomove the optical devices close to electrical device. Silicon photonicsis an important technology for moving optics closer to silicon. In thispatent application, we will disclose a high speed electrical opticsmultiple chip module device to achieve terabits per second speed, aswell as variations thereof.

In an alternative example, the present invention includes an integratedsystem on chip device. The device is configured on a single siliconsubstrate member. The device has a data input/output interface providedon the substrate member and configured for a predefined data rate andprotocol. The device has an input/output block provided on the substratemember and coupled to the data input/output interface. In an example,the input/output block comprises a Serializer/Deserializer (SerDes)block, a clock data recovery (CDR) block, a compensation block, and anequalizer block, among others. The device has a signal processing blockprovided on the substrate member and coupled to the input/output block.In an example, the signal processing block is configured to theinput/output block using a bi-direction bus in an intermediary protocol.The device has a driver module provided on the substrate member andcoupled to the signal processing block. In an example, the driver moduleis coupled to the signal processing block using a uni-directionalmulti-lane bus. In an example, the device has a driver interfaceprovided on the substrate member and coupled to the driver module andconfigured to be coupled to a silicon photonics device. In an example,the driver interface is configured to transmit output data in either anamplitude modulation format or a combination of phase/amplitudemodulation format or a phase modulation format. In an example, thedevice has a receiver module comprising a transimpedance amplifier (TIA)block provided on the substrate member and to be coupled to the siliconphotonics device using predefined modulation format, and configured tothe signal processing block to communicate information to theinput/output block for transmission through the data input/outputinterface. In an example, the device has a communication block providedon the substrate member and operably coupled to the input/output block,the signal processing block, the driver block, and the receiver block,among others. The device has a communication interface coupled to thecommunication block. The device has a control block provided on thesubstrate member and coupled to the communication block.

In an example, the signal processing block comprises a forward errorcorrection (FEC) block, a digital signal processing block, a framingblock, a protocol block, and a redundancy block, among others. Thedriver module is selected from a current drive or a voltage driver in anexample. In an example, the driver module is a differential driver orthe like. In an example, the silicon photonics device is selected froman electro absorption modulator (EAM) or electro optic modulator (EOM),or a Mach-Zehnder modulator (MZM). In an example, the amplifiedmodulation format is selected from non-return to zero (NRZ) format orpulse amplitude modulation (PAM) format. In an example, the phasemodulation format is selected from binary phase shift keying (BPSK) ornPSK. In an example, the phase/amplitude modulation is quad amplitudemodulation (QAM). In an example, the silicon photonic device isconfigured to convert the output data into an output transport data in awave division multiplexed (WDM) signal. In an example, the control blockis configured to initiate a laser bias or a modulator bias. In anexample, the control block is configured for laser bias and powercontrol of the silicon photonics device. In an example, the controlblock is configured with a thermal tuning or carrier tuning device eachof which is configured on the silicon photonics device. In an example,the SerDes block is configured to convert a first data stream of N intoa second data stream of M.

In an example, the invention provides an integrated system on chipdevice. The device has a single silicon substrate member and a datainput/output interface provided on the substrate member and configuredfor a predefined data rate and protocol. In an example, the device hasan input/output block provided on the substrate member and coupled tothe data input/output interface. The input/output block comprises aSerDes block, a CDR block, a compensation block, and an equalizer block,among others. The device has a signal processing block provided on thesubstrate member and coupled to the input/output block. In an example,the signal processing block is configured to the input/output blockusing a bi-direction bus in an intermediary protocol. In an example, thedevice has a driver module provided on the substrate member and coupledto the signal processing block. The driver module is coupled to thesignal processing block using a uni-directional multi-lane bus. In anexample, the device has a driver interface provided on the substratemember and coupled to the driver module and configured to be coupled toa silicon photonics device. The driver interface is configured totransmit output data in either an amplitude modulation format or acombination of phase/amplitude modulation format or a phase modulationformat in an example. The device has a receiver module comprising a TIAblock provided on the substrate member and to be coupled to the siliconphotonics device using predefined modulation format, and configured tothe signal processing block to communicate information to theinput/output block for transmission through the data input/outputinterface. In an example, the device has a communication block providedon the substrate member and operably coupled to the input/output blockand the signal processing block, the driver block, and the receiverblock, and others, although there may be variations. In an example, thedevice has a communication interface coupled to the communication blockand a control block provided on the substrate member and coupled to thecommunication block. In an example, the control block is configured toreceive and send instruction(s) in a digital format to the communicationblock and being configured to receive and send signals in an analogformat to communicate with the silicon photonics device.

In an example, the present invention provides a monolithicallyintegrated system on chip device configured for a multi-rate andselected format of data communication. In an example, the device has asingle silicon substrate member. The device has a data input/outputinterface provided on the substrate member and configured for apredefined data rate and protocol. In an example, the data input/outputinterface is configured for number of lanes numbered from four to onehundred and fifty. The device has an input/output block provided on thesubstrate member and coupled to the data input/output interface, whichhas a SerDes block, a CDR block, a compensation block, and an equalizerblock. In an example, the SerDes block is configured to convert a firstdata stream of N into a second data stream of M. In an example, each ofthe first data stream has a first predefined data rate at a first clockrate and each of the second data stream having a second predefined datarate at a second clock rate. As used herein the terms “first” and“second” do not necessarily imply order and shall be construed broadlyaccording to ordinary meaning. In an example, the device has a signalprocessing block provided on the substrate member and coupled to theinput/output block. The signal processing block is configured to theinput/output block using a bi-direction bus in an intermediary protocolin an example. The device has a driver module provided on the substratemember and coupled to the signal processing block. In an example, thedriver module is coupled to the signal processing block using auni-directional multi-lane bus. In an example, the device has a driverinterface provided on the substrate member and coupled to the drivermodule and configured to be coupled to a silicon photonics device. In anexample, the driver interface is configured to transmit output data ineither an amplitude modulation format or a combination ofphase/amplitude modulation format or a phase modulation format. Thedevice has a receiver module comprising a TIA block provided on thesubstrate member and to be coupled to the silicon photonics device usingpredefined modulation format, and is configured to the signal processingblock to communicate information to the input/output block fortransmission through the data input/output interface. In an example, thedevice has a communication block provided on the substrate member andoperably coupled to the input/output block, the signal processing block,the driver block, and the receiver block, and others, although there canbe variations. In an example, the device has a communication interfacecoupled to the communication block and a control block provided on thesubstrate member and coupled to the communication block.

In an example, the present invention provides a monolithicallyintegrated system on chip device configured for a multi-rate andselected format of data communication. In an example, the device has asingle silicon substrate member. The device has a data input/outputinterface provided on the substrate member and configured for apredefined data rate and protocol. In an example, the data input/outputinterface is configured for number of lanes numbered from four to onehundred and fifty, although there can be variations. In an example, thedevice has an input/output block provided on the substrate member andcoupled to the data input/output interface. In an example, theinput/output block comprises a SerDes block, a CDR block, a compensationblock, and an equalizer block, among others. In an example, the SerDesblock is configured to convert a first data stream of X into a seconddata stream of Y, where X and Y are different integers. Each of thefirst data stream has a first predefined data rate at a first clock rateand each of the second data stream has a second predefined data rate ata second clock rate in an example. In an example, the device has asignal processing block provided on the substrate member and coupled tothe input/output block. In an example, the signal processing block isconfigured to the input/output block using a bi-direction bus in anintermediary protocol. In an example, the device has a driver moduleprovided on the substrate member and coupled to the signal processingblock. In an example, the driver module is coupled to the signalprocessing block using a uni-directional multi-lane bus configured withN lanes, whereupon N is greater than M such that a difference between Nand M represents a redundant lane or lanes. In an example, the devicehas a mapping block configured to associate the M lanes to a pluralityof selected laser devices for a silicon photonics device. The devicealso has a driver interface provided on the substrate member and coupledto the driver module and configured to be coupled to the siliconphotonics device. In an example, the driver interface is configured totransmit output data in either an amplitude modulation format or acombination of phase/amplitude modulation format or a phase modulationformat. In an example, the device has a receiver module comprising a TIAblock provided on the substrate member and to be coupled to the siliconphotonics device using predefined modulation format, and configured tothe signal processing block to communicate information to theinput/output block for transmission through the data input/outputinterface. The device has a communication block provided on thesubstrate member and operably coupled to the input/output block, thesignal processing block, the driver block, and the receiver block, amongothers. The device has a communication interface coupled to thecommunication block and a control block provided on the substrate memberand coupled to the communication block.

In an example, the device has an integrated system on chip device. Thedevice has a single silicon substrate member and a data input/outputinterface provided on the substrate member and configured for apredefined data rate and protocol. In an example, the device has aninput/output block provided on the substrate member and coupled to thedata input/output interface. In an example, the input/output blockcomprises a SerDes block, a CDR block, a compensation block, and anequalizer block, among others. The device has a signal processing blockprovided on the substrate member and coupled to the input/output block.The signal processing block is configured to the input/output blockusing a bi-direction bus in an intermediary protocol. The device has adriver module provided on the substrate member and coupled to the signalprocessing block. In an example, the driver module is coupled to thesignal processing block using a uni-directional multi-lane bus. In anexample, the device has a driver interface provided on the substratemember and coupled to the driver module and configured to be coupled toa silicon photonics device. In an example, the driver interface isconfigured to transmit output data in either an amplitude modulationformat or a combination of phase/amplitude modulation format or a phasemodulation format. In an example, the device has a receiver modulecomprising a TIA block provided on the substrate member and to becoupled to the silicon photonics device using predefined modulationformat, and configured to the signal processing block to communicateinformation to the input/output block for transmission through the datainput/output interface. In an example, the device has a communicationblock provided on the substrate member and operably coupled to theinput/output block, the signal processing block, the driver block, andthe receiver block, and among others. The device has a communicationinterface coupled to the communication block and a control blockprovided on the substrate member and coupled to the communication block.In an example, the device has a variable bias block configured with thecontrol block. In an example, the variable bias block is configured toselectively tune each of a plurality of laser devices provided on thesilicon photonics device to adjust for at least a wavelength ofoperation, a fabrication tolerance, and an extinction ratio.

In an example, the present invention provides an integrated system onchip device having a self test using a loop back technique. In anexample, the device has a self-test block provided on the substrate, theself test block being configured to receive a loop back signal from atleast one of the digital signal processing block, the driver module, orthe silicon photonics device. In an example, the self test blockcomprises a variable output power switch configured to provide a stressreceiver test from the loop back signal.

In an example, the invention provides an integrated system on chipdevice having a redundant laser or lasers configured for each channel.In an example, the device has a plurality of laser devices configured onthe silicon photonics device. At least a pair of laser devices isassociated with a channel and coupled to a switch to select one of thepair of laser devices to be coupled to an optical multiplexer to providefor a redundant laser device.

In an example, the present invention provides an integrated system onchip device having a built-in self test technique. In an example, thedevice has a self test block configured on the silicon photonics deviceand to be operable during a test operation. In an example, the self testblock comprises a broad band source configured to emit electromagneticradiation from 1200 nm to 1400 nm or 1500 to 1600 nm to a multiplexerdevice. In an example, the broad band source can be an LED or othersuitable device. The device also includes a self test output configuredto a spectrum analyzer device external to the silicon photonics device.

The present invention achieves these benefits and others in the contextof known memory technology. However, a further understanding of thenature and advantages of the present invention may be realized byreference to the latter portions of the specification and attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following diagrams are merely examples, which should not undulylimit the scope of the claims herein. One of ordinary skill in the artwould recognize many other variations, modifications, and alternatives.It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this process andscope of the appended claims.

FIG. 1 is a simplified diagram of a single hybrid die (Both electricaland optics devices are fabricated on a single hybrid die) according toan embodiment of the present invention.

FIG. 2 is a simplified diagram of a multi-chip module according to anembodiment of the present invention.

FIG. 2A is a simplified diagram of an exemplary hybrid silicon photonicsdevice.

FIG. 3 is a simplified diagram of an electrical silicon die blockaccording to an embodiment of the present invention.

FIG. 4 is a simplified diagram of high speed serial link block accordingto an embodiment of the present invention.

FIG. 5 is a simplified diagram of a digital processing/signalpre-distortion block according to an embodiment of the presentinvention.

FIG. 6 is a simplified diagram of an electrical laser driver and TIAblock diagram according to an embodiment of the present invention.

FIG. 7 is a simplified diagram of a silicon photonic block diagramaccording to an embodiment of the present invention.

FIG. 8 is a simplified block diagram of a multi-chip module according toan alternative embodiment of the present invention.

FIG. 9 is a simplified block diagram of data flow according to anembodiment of the present invention.

FIG. 10 is a simplified diagram illustrating a redundant laserconfiguration at a drive stage according to an embodiment of the presentinvention.

FIG. 11 is a simplified diagram illustrating a built-in self test usingan optical loop back according to an embodiment of the presentinvention.

FIG. 12 is a simplified diagram illustrating a built-in self testconfigured for optical testing according to an embodiment of the presentinvention.

FIG. 13 is a simplified diagram illustrating a variable bias for opticalelements configured within a silicon photonic device according to anembodiment of the present invention.

FIG. 14 is a simplified diagram illustrating wavelength tuningconfigured to silicon photonic device according to an embodiment of thepresent invention.

FIG. 15 is a simplified block diagram of an interface for a siliconphotonics device according to an embodiment of the present invention.

FIG. 16 is a simplified diagram illustrating a laser configuration at atransmitter side of a silicon photonics device according to anembodiment of the present invention.

FIG. 17 is a simplified diagram illustrating a laser configuration at areceiver side of a silicon photonics device according to an embodimentof the present invention.

FIG. 18 is a simplified diagram illustrating a hybrid light source for asilicon photonics device according to an embodiment of the presentinvention.

FIG. 19 is a simplified diagram illustrating a wavelength control andlocking configuration with a silicon photonic device according to anembodiment of the present invention.

FIG. 20 is a simplified diagram illustrating a wavelength control andlocking configuration with a silicon photonics device according to analternative embodiment of the present invention.

FIGS. 21A-C are simplified diagrams illustrating a silicon photonicsdevice configured on high speed substrates according to embodiments ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

This present invention relates to telecommunication techniques. Morespecifically, various embodiments of the present invention provide acommunication interface that is configured to transfer data at highbandwidth over optical communication networks. In certain embodiments,the communication interface is used by various devices, such as spineswitches and leaf switches, within a spine-leaf network architecture,which allows large amount of data to be shared among servers.

In the last decades, with advent of cloud computing and data center, theneeds for network servers have evolved. For example, the three-levelconfiguration that have been used for a long time is no longer adequateor suitable, as distributed applications require flatter networkarchitectures, where server virtualization that allows servers tooperate in parallel. For example, multiple servers can be used togetherto perform a requested task. For multiple servers to work in parallel,it is often imperative for them to be share large amount of informationamong themselves quickly, as opposed to having data going back forththrough multiple layers of network architecture (e.g., network switches,etc.).

Leaf-spine type of network architecture is provided to better allowservers to work in parallel and move data quickly among servers,offering high bandwidth and low latencies. Typically, a leaf-spinenetwork architecture uses a top-of-rack switch that can directly accessinto server nodes and links back to a set of non-blocking spine switchesthat have enough bandwidth to allow for clusters of servers to be linkedto one another and share large amount of data.

In a typical leaf-spine network today, gigabits of data are shared amongservers. In certain network architectures, network servers on the samelevel have certain peer links for data sharing. Unfortunately, thebandwidth for this type of set up is often inadequate. It is to beappreciated that embodiments of the present invention utilizes PAM(e.g., PAM8, PAM12, PAM16, etc.) in leaf-spine architecture that allowslarge amount (up terabytes of data at the spine level) of data to betransferred via optical network.

The following description is presented to enable one of ordinary skillin the art to make and use the invention and to incorporate it in thecontext of particular applications. Various modifications, as well as avariety of uses in different applications will be readily apparent tothose skilled in the art, and the general principles defined herein maybe applied to a wide range of embodiments. Thus, the present inventionis not intended to be limited to the embodiments presented, but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

In the following detailed description, numerous specific details are setforth in order to provide a more thorough understanding of the presentinvention. However, it will be apparent to one skilled in the art thatthe present invention may be practiced without necessarily being limitedto these specific details. In other instances, well-known structures anddevices are shown in block diagram form, rather than in detail, in orderto avoid obscuring the present invention.

The reader's attention is directed to all papers and documents which arefiled concurrently with this specification and which are open to publicinspection with this specification, and the contents of all such papersand documents are incorporated herein by reference. All the featuresdisclosed in this specification, (including any accompanying claims,abstract, and drawings) may be replaced by alternative features servingthe same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

Furthermore, any element in a claim that does not explicitly state“means for” performing a specified function, or “step for” performing aspecific function, is not to be interpreted as a “means” or “step”clause as specified in 35 U.S.C. Section 112, Paragraph 6. Inparticular, the use of “step of” or “act of” in the Claims herein is notintended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.

Please note, if used, the labels left, right, front, back, top, bottom,forward, reverse, clockwise and counter clockwise have been used forconvenience purposes only and are not intended to imply any particularfixed direction. Instead, they are used to reflect relative locationsand/or directions between various portions of an object.

FIG. 1 is a simplified diagram of a single hybrid die (Both electricaland optics devices are fabricated on a single hybrid die) according toan embodiment of the present invention. In an example, the presentdevice 100 comprises a single hybrid communication module made ofsilicon material. The module comprises a substrate member 110 having asurface region, an electrical silicon chip 120 overlying a first portionof the surface region, an silicon photonics device 130 overlying asecond portion of the surface region, a communication bus coupledbetween the electrical silicon chip and the silicon photonics device, anoptical interface 131 coupled to the silicon photonics device 130, andan electrical interface 121 coupled to the electrical silicon die 120.

FIG. 2 is a simplified diagram of a multi-chip module according to anembodiment of the present invention. In an example, the present device200 comprises a single hybrid communication module. The module comprisesa substrate member 210 having a surface region, which can be a printedcircuit board or other member. The module comprises an electricalsilicon chip 220 overlying a first portion of the surface region, asilicon photonics device 230 overlying a second portion of the surfaceregion, a communication bus 240 coupled between the electrical siliconchip and the silicon photonics device, an optical interface 231 coupledto the silicon photonics device 230, and an electrical interface 221coupled to the electrical silicon die 220.

As shown in FIG. 1, the single hybrid die includes a hybrid siliconphotonics device having an electrical circuit for processing and controland a silicon photonics module. In an example, the hybrid siliconphotonics device is described in U.S. Pat. No. 8,380,033, in the name ofFang, et al. issued Feb. 19, 2013, hereby incorporated by reference.FIG. 2A shows a simplified block diagram of an exemplary hybrid siliconphotonics device.

In this example, electro-optic device 200 includes a siliconsemiconductor slab including silicon top layer 201, vertical confinementlayer 202 and silicon substrate 203. Alternatively, substrate layer 203may be a diamond substrate, a glass substrate, or any functionalequivalent. Vertical confinement layer 202 may be formed of anydielectric material suitable for confining an optical mode (e.g., layer201 may be a silicon dioxide layer, a silicon nitride layer, or anyfunctionally equivalent insulating layer with a refractive index lowerthan silicon top layer 201).

Device 200 further includes a III-V semiconductor slab including p-typelayer 208, active layer 209 and n-type layer 210 (thereby forming aP-I-N diode). The term “p-type layer,” as used herein, describes a layercomprising a material that has more positive carriers (i.e., holes) thannegative carriers (i.e., electrons). The term “n-type layer,” as usedherein, describes a layer comprising a material that has more negativecarriers than positive carriers.

Alternatively, layer 208 may be an n-type layer, and layer 210 may be ap-type layer. Or, layers 208 and 210 may be n-type layers, while activeregion 209 may include a tunnel junction to convert n-type majoritycarriers to p-type majority carriers. This avoids the associated opticaland microwave loss of p-type materials due to the use of p-dopants.

III-V semiconductor materials have elements that are found in group IIIand group V of the periodic table (e.g., Indium Gallium ArsenidePhosphide, Gallium Indium Arsenide Nitride). The carrier dispersioneffects of III-V based materials may be significantly higher than insilicon based materials for bandgaps closer to the wavelength of thelight being transmitted or modulated, as electron speed in III-Vsemiconductors is much faster than that in silicon. In addition, III-Vmaterials have a direct bandgap which is required for the most efficientcreation of light from electrical pumping. Thus, III-V semiconductormaterials enable photonic operations with an increased efficiency oversilicon for both generating light and modulating the refractive index oflight.

Active layer 209 is of a III-V semiconductor with high electro-opticefficiency, i.e., the absorption coefficient (i.e., the imaginaryportion of the complex refractive index) and the refractive index (i.e.,the real portion of the complex refractive index) of active layer 209 iseasily affected by either the Franz Kheldysh effect if active layer 209comprises bulk material (e.g., intrinsic Indium Gallium ArsenidePhosphide or Indium Aluminum Gallium Arsenide or the Quantum ConfinedStark Effect if active layer 209 comprises multiple quantum wells.

Optical waveguide 250 is formed by ridge 260 (which is “bolded” or“thicker” in the figure for illustrative purposes only), including ridgesides 261 and 262. It is clear that in this embodiment, waveguide 250 isformed by features in the III-V region of device 200 as opposed to beingformed by features in the silicon region of the device, whereinwaveguide is formed by voids included in silicon top region. Thus, thesilicon and III-V regions of device 200 have a greater contact area thandevices in the prior art (where layer 210 was continuously coupled tolayer 201).

Overclad regions 207 may be formed on the device to improve mechanicalstability, and may be of any material used to form vertical confinementlayer 202 or any material with a lower refractive index than layer 208.Overclad regions 207 further provide vertical optical confinement andpassivation as described below. The areas adjacent to ridge sides 261and 262 provide optical confinement if left as voids (i.e., areascomprising air), but that forming overclad regions 207 provides formechanical stability in addition to optical confinement.

Thus, optical mode 213 is vertically confined by vertical confinementlayer 202, ridge 260 and overclad regions 207 while being laterallyconfined by ridge sides 261 and 262. Said ridge sides also confineinjection current from electrode 206 towards the portion of active layer209 that overlaps optical mode 213. The need for the etched regions andimplanted regions is eliminated in the example shown above.

It is understood that the optical device of FIG. 2A may be used toamplify, modulate or detect light transmitted through the opticalwaveguide of the device by applying an electrical difference tocomplimentary electrodes 206 and 212 to either forward bias (i.e., foramplification) or reverse bias (i.e., for modulation or detection) thestructure. The complex refractive index (i.e., at least one of the realand the imaginary refractive index) of at least the portion of activelayer 209 included in optical mode 213 changes based on an electricaldifference (e.g., electrical voltage, electrical field) applied toelectrodes 206 and 212. These changes to the refractive index (orindexes) are proportional to the strength of the electrical differenceapplied to electrodes 206 and 212.

In this example, electrodes 212 are coupled to n-type layer 210. Thus,it is to be understood that there is no electrical conduction throughsilicon top layer 201. As opposed to variations where electricalconduction does occur through the silicon top layer of a device,resistance is high as it determined by thin layer 210; however, thereare less processing steps needed to create device 200 and no conductivebond is required to couple the silicon region with the III-V region(i.e., no conductive bond is required to couple layers 210 and 201).

Other examples of silicon photonic devices are manufactured by IntelCorporation of Santa Clara, Calif., Skorpis Technology, Inc. 5600 EubankBlvd. NE Suite 200, Albuquerque, N. Mex. 87111, Luxtera, Inc. of 2320Camino Vida Roble, Carlsbad, Calif. 92011, Mellanox Technologies, Inc.350 Oakmead Parkway, Suite 100 Sunnyvale, Calif. 94085, and amLightwire, Inc. Headquartered in Allentown, Pa. (now Cisco Systems,Inc., Corporate Headquarters, 170 West Tasman Dr., San Jose, Calif.95134) among others.

FIG. 3 is a simplified diagram of an electrical silicon die blockaccording to an embodiment of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. In an embodiment, theelectrical silicon die block 300 is an electrical signal processingblock that connects a low speed electrical interface to a high speedoptical interface. There are several elements to this block diagram. Asshown, the electrical silicon die block 300 includes a high speed seriallink 310, a digital signal processing/pre-distortion unit 320, and alaser modulator driver and TIA unit 330. The high speed serial link 310includes an input/output block having an RX (receiving) functional unitand a TX (transmitting) function unit coupled to a phase lock loopcircuit. For example, the TX function unit drives the loopback signalsthat are processed by the RX functional unit. Using the high speedserial link 310, the data first is able to be converted from the manyparallel streams of lower speed data into a high speed serial stream(there may be more than one such high speed stream depending on thetotal data rate). The digital signal processing/pre-distortion unit 320is configured to process or convert digital electrical signal back andforth to optical signal and conduct all signal modulation, errorencoding/decoding, and signal distortion compensation. The high speedstreams converted by the high speed serial link 310 are then encoded anddigitally compensated to account for distortions in the transmit andreceive paths. The final interface to the optical components is achievedvia the modulator driver (transmit path) and the transimpedanceamplifier (receive path). The laser modulator driver and TIA unit 330 isconfigured to control the optical device (such as the optics siliconphotonics die on the part of the multi-chip module in FIG. 2). In aspecific embodiment, the electrical silicon die block 300 is a singlehybrid die as part of the multi-chip module shown in FIG. 2.

FIG. 4 is a simplified diagram of high speed serial link block accordingto an embodiment of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. As shown, the present device 400 is a high speedserial link block which provides details of the signal interface betweenthe high speed optical and the lower speed electrical sides. In anembodiment, the high speed serial link block comprises multiple BitsFlash Samplers 450 and an all-digital SerDes core unit 410 powered undera low Vdd power supply. The samplers 450 are part of RX functional unitof the input/output block 310. The all-digital SerDes core unit 410comprises an all digital phase lock loop (PLL) block 420, a fast lockCDR block 430, and Digital offset calibrations and logics block 440,also belonging to the RX functional unit (310 of FIG. 3). In anotherembodiment, the high speed serial link block is an electricalinput/output block provided on either a single chip or a silicon die ofpackage substrate member and coupled to the data input/output interface.Some of the essential components of the electrical input/output blockare CDR (clock and data recovery circuits), PLL (phase lock loops), andSerDes (Serializers and Deserializers). In an example, the input/outputblock comprises a SerDes block, a CDR block, a compensation block, andan equalizer block, among others. The output of equalizer includesreceiver input. These circuits in combination convert multiple streamsof input data (electrical side) to fewer streams of output data (opticalside). These circuits also need to be calibrated and controlled tooperate correctly. In a specific embodiment, the serial link block 310of FIG. 3 can be configured like block 400.

FIG. 5 is a simplified diagram of a digital processing/signalpre-distortion block according to an embodiment of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. One of ordinary skill in the art wouldrecognize many variations, alternatives, and modifications. As shown,the digital processing/signal pre-distortion block 500 comprises atleast an Error Encoding/Decoding block 510, an OpticalDistortion/Electrical Compensation (EDC) block 520, and a ModulationConversion block 530. In an example, it shows the details of a possibleimplementation of the electronic processing blocks in the transmit andreceive paths. In an alternative embodiment, some of those blocks may beconfigured differently in the transmit versus the receive path. One ofthe essential blocks is the Error Encoding/Decoding block 510 whichperforms data error control coding. As additional data bits are added toblocks of signal data in such a way that when errors occur they may becorrectable in the receive path. Modern error control codes aresophisticated that they can correct, e.g., up to 1 error in every 100bits with modest data overhead and latency. Optical distortioncompensation block 520 helps compensate for impairments in the opticaland electrical transmission paths. These could include compensation of,e.g., bandwidth limitations and inter-symbol interference. Themodulation conversion block 530 codes and decodes the multi-levelhigher-order modulation signals that are used at the transmitter andreceiver, and converts them to the simple two-level NRZ format used inthe lower speed interfaces.

FIG. 6 is a simplified diagram of an electrical laser driver and TIAblock diagram according to an embodiment of the present invention. Thisdiagram is merely an example, which should not unduly limit the scope ofthe claims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, the top partcircuit (A) of an electrical laser driver and TIA block 600 includes anedge rate control circuit 610 coupled to a swing and common mode voltageadjustable driver 620. In an implementation, the driver 620 will be usedfor the modulator and the receiver circuit for a photo diode detector(to be shown in FIG. 7 below). The electrical output of the top circuit(A) is used to drive the modulator. The modulator imprints theelectrical signal input on to the optical carrier. The driver and TIAblock 600 can also include a limiting amplifier 630 coupled to a TIA640, which can be coupled to an input bandwidth control block 650. Theoutput of the photo diode detector is the input to the bottom partcircuit (B) of the electrical laser driver and TIA block 600. Thiscircuit converts the current signal from the photo diode detector into avoltage signal which can then be processed by other circuits. In anexample, the electrical laser driver and TIA block 600 is block 330included in the electrical silicon die block shown in FIG. 3.

FIG. 7 is a simplified diagram of a silicon photonic block diagramaccording to an embodiment of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. As shown, in an embodiment,a silicon photonic block 700 includes a substrate 710, a continuous wave(CW) distributed feedback (DFB) laser block 720, an electro-absorptionmodulator or MZ modulator 730, control loops 740, and photo diodedetectors 750. In a specific embodiment, the silicon photonic block 700includes common blocks of an optical sub-system including control loops.The transmit path of the optical sub-system includes a laser source 720which can be selected from a CW (continuous wave) DFB (distributedfeedback) laser among others. The laser source 720 provides the opticalcarrier. The output from the laser source 720 is optically coupled intothe laser modulator 730. The electrical data is converted to optical viathe modulator for modulating the optical signal directly from the lasersource 720. The modulator 730 may be an electro-absorption modulator ora Mach-Zehnder (MZ) modulator, or others depending on embodiments. Theoutput signal from the modulator 720 is then coupled to a fiber (notshown) for external transmission. The receive path of the opticalsub-system includes the optical signal from the fiber coupled into oneor more photo diode detectors 750. The photo diode detector 750 convertsthe optical data into electrical data. The control loops 740 are neededto correctly bias the laser source 720, the modulator 730, and the oneor more photo diode detectors 750. The bias control signals may includecurrent or voltage outputs used to setup the laser source, modulator,and the photo diode detector correctly. The control output signals mayalso be continually adjusted using the feedback from the devicesthemselves.

FIG. 8 is a simplified block diagram of a multi-chip module according toan alternative embodiment of the present invention. As shown, thepresent invention includes an integrated system on chip device. Thedevice 800 is configured on a single silicon substrate member. Thedevice 800 has a data input/output interface provided on the substratemember and configured for a predefined data rate and protocol. Thedevice 800 has an input/output block 820 provided on the substratemember and coupled to the data input/output interface. In an example,the input/output block 820 comprises a SerDes block, a CDR block, acompensation block, and an equalizer block, among others. The device 800has a signal processing block 810 provided on the substrate member andcoupled to the input/output block 820. In an example, the signalprocessing block 810 is configured to the input/output block 820 using abi-direction bus in an intermediary protocol. The device 800 has adriver module 860 provided on the substrate member and coupled to thesignal processing block 810. In an example, the driver module 860 iscoupled to the signal processing block 810 using a uni-directionalmulti-lane bus. In an example, the device 800 has a driver interfaceprovided on the substrate member and coupled to the driver module 860and configured to be coupled to a silicon photonics device 870. In anexample, the driver interface is configured to transmit output data ineither an amplitude modulation format or a combination ofphase/amplitude modulation format or a phase modulation format. In anexample, the device 800 has a receiver module 850 comprising a TIA blockprovided on the substrate member and to be coupled to the siliconphotonics device 870 using predefined modulation format, and configuredto the signal processing block 810 to communicate information to theinput/output block 820 for transmission through the data input/outputinterface. In an example, the device 800 has a communication block 830provided on the substrate member and operably coupled to theinput/output block 820, the signal processing block 810, the driverblock 860, and the receiver block 850, among others. The device 800 hasa communication interface coupled to the communication block 830. Thedevice 800 has a control block 840 provided on the substrate member andcoupled to the communication block.

In an example, the signal processing block 810 comprises a FEC block, adigital signal processing block, a framing block, a protocol block, anda redundancy block, among others. The driver module is selected from acurrent drive or a voltage driver in an example. In an example, thedriver module 860 is a differential driver or the like. In an example,the silicon photonics device 870 is selected from an electro absorptionmodulator (EAM) or electro optic modulator (EOM), or a Mach-Zehnder(MZ). In an example, the amplified modulation format is selected fromNRZ format or PAM format. In an example, the phase modulation format isselected from BPSK or nPSK. In an example, the phase/amplitudemodulation is QAM. In an example, the silicon photonic device 870 isconfigured to convert the output data into an output transport data in aWDM signal. In an example, the control block 840 is configured toinitiate a laser bias or a modulator bias. In an example, the controlblock 840 is configured for laser bias and power control of the siliconphotonics device 870. In an example, the control block 840 is configuredwith a thermal tuning or carrier tuning device each of which isconfigured on the silicon photonics device 870. In an example, theSerDes block is configured to convert a first data stream of N into asecond data stream of M.

FIG. 9 is a simplified block diagram of data flow according to anembodiment of the present invention. As show is a stream of incomingdata, which processed through multiple blocks. The blocks 900 include,among others, forward error correction 910, and other encoding 920,multi-level coding, pre-compression, and digital to analog coding. Theblocks 900 also include non-DSP forward error correction 930, and ablock corresponding to a laser diode or driver 940, among others. In anexample, in the absence of a FEC from a host process, techniques includeuse of CDR2 type FEC, which is internal to the CMOS chip. In an example,FEC can be striped across each or all of data lanes. Of course, therecan be variations, modifications, and alternatives.

FIG. 10 is a simplified diagram illustrating a redundant laserconfiguration 1000 at a drive stage according to an embodiment of thepresent invention. In an example, the invention provides an integratedsystem-on-chip device 1010 as a fully redundant system having aredundant laser or lasers configured for each channel. The device 1010can have a mod driver array 1020 and a TIA/LA array 1021. In an example,the device 1010 has a plurality of laser devices configured on thesilicon photonics device. At least a pair of laser devices 1030, 1031 isassociated with a channel and coupled to a switch 1050 to select one ofthe pair of laser devices to be coupled to an optical multiplexer toprovide for redundant laser devices 1040, 1041. The worst case is tohave 2 times total number of wavelengths with twice in chip size. In anembodiment, the switch is a Mach-Zehnder Interferometer (MZI) switchused to switch between a λ1 and a redundant λ1′. Or it could be apassive coupler. In another embodiment, it preserves the size of thewavelength multiplexer so that no additional λ channels are needed.Note, the integrated system-on-chip device doesn't have to operate theredundant λ1′ until needed, therefore no power consumption penalty isapplied.

FIG. 11 is a simplified diagram illustrating a built-in self test 1100using an optical loop back according to an embodiment of the presentinvention. As shown are a TX multiplexer 1110 and an RX multiplexer 1120for a silicon photonics device. In an example, the present inventionprovides an integrated system on chip device having a self test using aloop back technique. In an example, the device has a self-test blockprovided on the substrate. In an example, the self test block isconfigured to receive a loop back signal from at least one of thedigital signal processing block, the driver module, or the siliconphotonics device. In an example, the self test block comprises avariable output power switch configured to provide a stress receivertest from the loop back signal. Also shown is an isolation switch 1140between RX and TX. Optical couplers 1130 and 1131 are coupled to themultiplexer 1110 and an RX multiplexer 1120, respectively, as well asthe isolation switch 1140.

In an example, the present technique allows a loop back test capabilityon the device, which is now a silicon photonic application specificintegrated circuit or a communication system on chip device, asdescribed. In an example, the technique is provided for diagnostic andsetup during power up sequence. In an example, an optical tap coupler onthe output side connected to the input side as shown. In an example asshown, x (e.g., <10%) is selected to reduce and/or minimize an impact anoutput power as well an impact at the input power given that input poweris generally much lower than the output power. In an example, to preventcrosstalk in the present loop back path, an isolation switch has beenconfigured as shown. In an example, without the isolation switch thereis undesirably direct crosstalk between the output and input as shown.In an example, about 30 dB isolation is included to prevent coherentcrosstalk. Of course, there can be variations.

FIG. 12 is a simplified diagram illustrating a built-in self test 1200configured for optical testing according to an embodiment of the presentinvention. In an example, the present invention provides an integratedsystem on chip device having a built-in self test technique. As shownare a TX multiplexer 1210 and an RX multiplexer 1220 for a siliconphotonics device. A broad band source 1230 is coupled to each of themultiplexers. Multiple sources can also be included. In an example, thedevice has a self test block configured on the silicon photonics deviceand to be operable during a test operation. In an example, the self testblock comprises a broad band source configured to emit electromagneticradiation from 1200 nm to 1400 nm or 1500 to 1600 nm to a multiplexerdevice. In an example, the broad band source 1230 can be an LED or othersuitable device. The device also includes a self test output configuredto a spectrum analyzer device external to the silicon photonics device.In an example, the technique can be provided during a calibrationprocess. That is, if after calibration, a center λ of each multiplexerchanged, the present technique including built-in light source willquantify or indicate the change in an example. In an example, thebroadband source 1230 in silicon photonics is a light source with nooptical feedback, although there can be variations.

FIG. 13 is a simplified diagram illustrating a variable bias for opticalelements configured in a silicon photonic device according to anembodiment of the present invention. As shown schematic configuration ofusing variable bias for modulation transfer provided for opticalelements. In an example, the device has an integrated system on chipdevice having a capability selectively adjust each optical modulator toaccommodate for fabrication tolerances, wavelength operation, and/orextinction ratio, among other parameters. The device has a singlesilicon substrate member and a data input/output interface provided onthe substrate member and configured for a predefined data rate andprotocol. In an example, the device has an input/output block providedon the substrate member and coupled to the data input/output interface.In an example, the input/output block comprises a SerDes block, a CDRblock, a compensation block, and an equalizer block, among others. Thedevice has a signal processing block provided on the substrate memberand coupled to the input/output block. The signal processing block isconfigured to the input/output block using a bi-direction bus in anintermediary protocol. The device has a driver module provided on thesubstrate member and coupled to the signal processing block.

In an example, the driver module is coupled to the signal processingblock using a uni-directional multi-lane bus. In an example, the devicehas a driver interface provided on the substrate member and coupled tothe driver module and configured to be coupled to a silicon photonicsdevice. In an example, the driver interface is configured to transmitoutput data in either an amplitude modulation format or a combination ofphase/amplitude modulation format or a phase modulation format. In anexample, the device has a receiver module comprising a TIA blockprovided on the substrate member and to be coupled to the siliconphotonics device using predefined modulation format, and configured tothe signal processing block to communicate information to theinput/output block for transmission through the data input/outputinterface. In an example, the device has a communication block providedon the substrate member and operably coupled to the input/output block,the signal processing block, the driver block, and the receiver block,and among others. The device has a communication interface coupled tothe communication block and a control block provided on the substratemember and coupled to the communication block.

In an example, the device has a variable bias block 1300 configured withthe control block. In an example, the variable bias block is configuredto selectively tune each of a plurality of laser devices provided on thesilicon photonics device to adjust for at least a wavelength ofoperation, a fabrication tolerance, and an extinction ratio. As shown isa plurality of driver blocks 1320. Each of the driver blocks 1320 iscoupled to a voltage rail, and is configured with a variable voltagedevice 1310 to selectively tune each of the laser devices. In anexample, each of the laser devices can be configured with an opticalmodulator(s) such as electro-absorption modulators, electro-opticalmodulators, among others, which often couple to a direct current poweror bias. In an example, the DC bias is a function of wavelength ofoperation and also of fabrication tolerances, among other factors. In anexample, the present bias circuitry accommodates and/or corrects for anybias variations, while desirably controlling power. Of course, there canbe variations, modifications, and alternatives.

FIG. 14 is a simplified diagram illustrating wavelength tuningconfigured to silicon photonic device according to an embodiment of thepresent invention. In an example, the present tunable laser uses a setof rings with resonant frequencies that a slightly different. In anexample, the technique use a vernier effect to tune the laser over awide frequency range—limited by the bandwidth of the gain region. In anexample, the vernier desirably would be held in lock with respect to oneanother. In an example, the technique uses a dither frequency on one ofthe biases (e.g., heater) and lock the ring to the maximum transmissionof the second ring, although there can be variations. As shown in graph1401, resonant combs are generally misaligned in an example. Whenthermally tuned, techniques can be used to selectively align one of thecombs to another comb or spatial reference as shown in graph 1402. In anexample, to maintain alignment, the technique dithers the signal to oneof the rings. Of course, there can be variations, alternatives, andmodifications.

FIG. 15 is a simplified block diagram of a control interface for asilicon photonics device according to an embodiment of the presentinvention. In an example, the control interface is provided tocommunicate between the control block and the silicon photonics device(see FIG. 8). The control interface 1500 includes one or more of amodulator bias voltage input 1511, a laser DC bias current input 1512, aphotocurrent or set output 1521, a power monitor current/voltage output1522, a photodetector bias input 1513, a heater current/voltage input1514, a photocurrent from input signal or set output 1523, a wavelengthmonitor voltage/current/resistance output 1524, among other elements.The modulator bias input 1511 can be either RF or DC voltage for controlboth amplitude modulator and phase modulator to convert electrical datainto WDM optical data within the silicon photonics device. The laser DCbias current input 1512 is used to control the gain or active region ofthe laser. The photodetector bias input 1513 is used to control adetector coupled with a tapped portion of the muxed light at output portof the silicon photonics device. The heater current/voltage input 1514is using both current and voltage to control one or more thermoelectrictuner to determining a desired laser operation point including a lockedwavelength per each channel and a desired power. All these input signalsare control signals used by the control block (see FIG. 8). Of course,there can be variations.

The photocurrent or set output 1521 is a feedback from the siliconphotonics device, which is used for the control block to adjust the oneor more input signals mentioned above or set based on the opticalperformance. The power monitor current/voltage output 1522 is feedbackfor determining desired laser power. The photocurrent from input signalor set output 1523 and wavelength monitor voltage/current/resistanceoutput 1524 are other feedback signals processed by the controlinterface 1500 for properly operating the silicon photonics device. Allthese output or feedback signals are employed in an optical loopbackscheme. Of course, there can be other variations.

FIG. 16 is a simplified diagram illustrating a laser configuration 1600at a transmitter side of a silicon photonics device according to anembodiment of the present invention. The silicon photonics device is oneassociated with the system-on-chip device illustrated in FIG. 8. Asshown are a plurality of laser devices 1620 arranged in differentchannels with different wavelengths numbered from wavelength λ₁ toλ_(n), each of which has a modulator device 1640, and are collectivelycoupled to a spectral multiplexer 1660. Each of the laser devices 1620are coupled to a pair of control blocks, such as blocks 1611 and 1612,and monitor blocks 1630. The spectral multiplexer 1660 is coupled to afiber interface 1670. Each channel has two laser drivers for controllingoptical signals either by DC current or DC and Dither frequency, beforethe laser active region, a wavelength controller and locker, a modulatordevice for tuning the laser based on the original electrical data bits,and are collectively coupled to a spectral multiplexer. The spectralmultiplexer is coupled to a fiber interface for transmitting out a WDMsignal representing the original data 1G, 4G, 10G, or 100G, among otherswith multi-rate format. As shown, alternatively, a broadband source isalso included in parallel with the laser configuration at thetransmitter side of the silicon photonics device, as previously noted.

FIG. 17 is a simplified diagram illustrating a laser configuration 1700at a receiver side of a silicon photonics device according to anembodiment of the present invention. The silicon photonics device is oneassociated with the system-on-chip device illustrated in FIG. 8. Asshown are a plurality of detectors 1710 arranged for each channel withwavelength λ₁ to λ_(n), each of which has a oscillator device 1730, andare collectively coupled to a spectral multiplexer 1750. Each of thephotodetector blocks 1710 can be coupled to hybrid blocks 1720. Thespectral multiplexer is coupled to a fiber interface 1760. The spectralmultiplexer 1750 is coupled to a fiber interface to receive the incomingWDM signals. After each wavelength is demultiplexed, it is mixed in thehybrid block 1720 with a local oscillator signal from the oscillatordevice 1730 per each channel. The detector per channel is configured toconvert the hybrid optical signals into photocurrent as electricalsignals. As shown in FIG. 17, a broadband source 1740 is included inparallel, as previously noted.

FIG. 18 is a simplified diagram illustrating a hybrid light source 1800for a silicon photonics device according to an embodiment of the presentinvention. As shown is a silicon substrate 1810 for photonics devices,and overlying buried oxide region 1820, and an overlying crystallinesilicon material 1830 configured for a waveguide or guides. Of course,there can be other variations, modifications, and alternatives.

FIG. 19 is a simplified diagram illustrating a wavelength control andlocking configuration with a silicon photonic device according to anembodiment of the present invention. As shown, device 1901 shows a laserdevice coupled to control blocks, and a modulator block. For eachwavelength (channel) two control drivers are used. Driver #2 is drivenby a fixed DC bias current setting as described as Input 1512 in FIG.15. Driver #1 is driven by the DC bias current combined a frequencydither signal generated by variable bias block. The both wavelengthcontrol signals are combined to drive operation of the laser activeregion. A monitor device follows the laser active region to monitor thelaser power and wavelength by providing feedback signals in terms ofcurrent and voltage (e.g., 1523, 1524 in FIG. 15). The monitor blockcoupled to the modular and laser device is also coupled in series to aphotocurrent detect circuit to TIA with bandwidth 2f-4f block, a minimumdetect circuit to derivative block, and the variable bias setting block.Only one control signal (e.g., #1) is applied with dither in the monitordevice. A photocurrent detect circuit of the monitor device is coupledto a transimpedance amplifier with bandwidth of 2-times to 4-times thecorresponding signal frequency. Graph 1902 shows the signal at themonitor #1 block when dither is applied, showing the derivative signalin the bottom graph. The dither-applied control signal after thephotocurrent detect circuit further is processed by a minimum detectcircuit to convert to a derivative signal. Graph 1903 shows the effectof applying dither to one comb on the wavelengths produced. Thisself-test configuration can also be used in the detections of the oddharmonics. Accordingly a variable control bias setting is determined andsent back to the laser driver #1. As the wavelength is controlled andlocked by the above feedback control configuration, a modulator iscoupled before the output port to provide signal modulation (in bothamplitude and phase) in accordance with original data bits. Of course,there can be other variations, modifications, and alternatives.

FIG. 20 is a simplified diagram illustrating a wavelength control andlocking configuration with a silicon photonics device according to analternative embodiment of the present invention. The device of 2001shows a similar configuration to device 1901 of FIG. 19. Graph 2002shows the signal after the detect circuit when dither is applied to oneof the controls. Graph 2003 shows the application of dither to one comb,similar to graph 1903 of FIG. 19. This is a method with some differenceadded into the transimpedance amplifier for processing the photocurrentdetection in the monitor device, wherein the bandwidth of thetransimpedance amplifier is still from 2-times (2f) to 4-times (4f) thecorresponding signal frequency but a bandpass filter at 2f and 4f (or at2 kf in principle for k=1, 2, 3, . . . ) is added, compared to themethod mentioned in FIG. 19. Again, the dither-applied control signalafter the photocurrent detect circuit further is processed by a minimumdetect circuit to convert to a reversed derivative signal. Of course,there can be other variations, modifications, and alternatives.

FIGS. 21 A-C are simplified diagrams illustrating a silicon photonicsdevice configured on high speed substrates according to embodiments ofthe present invention. FIG. 21A shows device 2101 wherein a high speedASIC is configured overlying a first region of a high speed substrateand coupled to one or more first contact pads. At least one of the firstcontacts is coupled to one of one or more second contact pads.Similarly, at least one of the second contacts is coupled to one of oneor more third contact pads. A high speed probe is shown at the secondcontacts.

In an embodiment, the high speed substrate is designed such that it hasa series of traces and via connections to characterize its bandwidth andloss. The probe pads may be staggered and/or placed at differentdistances from the ASIC to characterize the ASIC drive and substratebandwidth properties. This test can be done in manufacturing to screenout bad ASIC's before the next die is attached. Typically, lower costdies are screened out before expensive ones. The connections may also bedaisy chained on the substrate to test a number of vias and connectionsin series to extract the equivalent circuit model for each.

FIG. 21B shows device 2102 wherein a silicon photonics device isconfigured overlying a second region of the high speed substrate. Thesilicon photonics device is coupled to the one or more second contacts.The high speed ASIC and the silicon photonics device are coupled via thefirst and second contacts. Here, the high speed probe is shown at thethird contacts.

In an embodiment, the BIST (built-in self-test) capability in thesilicon photonics chip can be used to convert the optical signal to theelectrical equivalent and test it on the high speed substrate. The highspeed substrate can also have resistors, capacitors, etc., forterminations and appropriate electrical loads. In the normal use case,the signals from the silicon photonics device will terminate in the highspeed ASIC completely in the self-test loop. There are diagnostic caseswhere external termination may be provided on the substrate and signalquality is verified.

FIG. 21C shows device 2103 wherein another high speed ASIC is configuredoverlying a third region of the high speed substrate. This second highspeed ASIC is coupled to the one or more third contacts. The second highspeed ASIC and the silicon photonics device are coupled via the secondand third contacts. High speed electrical ASIC and silicon photonicsASIC can be cascaded for testing and characterization.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. Therefore, the above description and illustrations should not betaken as limiting the scope of the present invention which is defined bythe appended claims.

What is claimed is:
 1. A monolithically integrated system on chipdevice, the device comprising: a single silicon substrate member; a datainput/output interface provided on the substrate member and configuredfor a predefined data rate and protocol; an input/output block providedon the substrate member and coupled to the data input/output interface,the input/output block comprising a SerDes block, a CDR block, acompensation block, and an equalizer block; a signal processing blockprovided on the substrate member and coupled to the input/output block,the signal processing block configured to the input/output block using abi-direction bus in an intermediary protocol; a driver module providedon the substrate member and coupled to the signal processing block, thedriver module coupled to the signal processing block using auni-directional multi-lane bus; a driver interface provided on thesubstrate member and coupled to the driver module and configured to becoupled to a silicon photonics device, the driver interface beingconfigured to transmit output data in either an amplitude modulationformat or a combination of phase/amplitude modulation format or a phasemodulation format; a receiver module comprising a TIA block provided onthe substrate member and to be coupled to the silicon photonics deviceusing predefined modulation format, and configured to the signalprocessing block to communicate information to the input/output blockfor transmission through the data input/output interface; acommunication block provided on the substrate member and operablycoupled to the input/output block, the signal processing block, thedriver block, and the receiver block; a communication interface coupledto the communication block; a control block provided on the substratemember and coupled to the communication block; a control interfaceprovided to communicate between the control block and the siliconphotonics device, the control interface comprising: a modulator biasvoltage input; a laser DC bias current input; a photocurrent or setoutput; a power monitor current/voltage output; a photodetector biasinput; a heater current/voltage input; a photocurrent from input signalor set output; a wavelength monitor voltage/current/resistance output.2. The device of claim 1 wherein the signal processing block comprises aFEC block, a digital signal processing block, a framing block, aprotocol block, and a redundancy block.
 3. The device of claim 1 whereinthe driver module is selected from a current drive or a voltage driver.4. The device of claim 1 wherein the driver module is a differentialdriver.
 5. The device of claim 1 wherein the amplified modulation formatis selected from NRZ format or PAM format.
 6. The device of claim 1wherein the phase modulation format is selected from BPSK or nPSK. 7.The device of claim 1 wherein the signal processing block comprises aFEC block, a digital signal processing block, a framing block, aprotocol block, and a redundancy block; wherein the amplified modulationformat is a PAM format.
 8. The device of claim 1 wherein thephase/amplitude modulation is QAM.
 9. The device of claim 1 wherein thesilicon photonic device is configured to convert the output data into anoutput transport data in a WDM signal.
 10. The device of claim 1 whereinthe control block is configured to initiate a laser bias or a modulatorbias.
 11. The device of claim 1 wherein the control block is configuredfor laser bias and power control of the silicon photonics device. 12.The device of claim 1 wherein the control block is configured with athermal tuning or carrier tuning device each of which is configured onthe silicon photonics device.
 13. The device of claim 1 wherein theSerDes block is configured to convert a first data stream of N into asecond data stream of M.
 14. A monolithically integrated system on chipdevice, the device comprising: a single silicon substrate member; a datainput/output interface provided on the substrate member and configuredfor a predefined data rate and protocol; an input/output block providedon the substrate member and coupled to the data input/output interface;a signal processing block provided on the substrate member and coupledto the input/output block, the signal processing block configured to theinput/output block using a bi-direction bus in an intermediary protocol;a driver module provided on the substrate member and coupled to thesignal processing block, the driver module coupled to the signalprocessing block using a uni-directional multi-lane bus; a driverinterface provided on the substrate member and coupled to the drivermodule and configured to be coupled to a silicon photonics device, thedriver interface being configured to transmit output data in either anamplitude modulation format or a combination of phase/amplitudemodulation format or a phase modulation format; a receiver modulecomprising a TIA block provided on the substrate member and to becoupled to the silicon photonics device using predefined modulationformat, and configured to the signal processing block to communicateinformation to the input/output block for transmission through the datainput/output interface; a communication block provided on the substratemember and operably coupled to the input/output block, the signalprocessing block, the driver block, and the receiver block; acommunication interface coupled to the communication block; a controlblock provided on the substrate member and coupled to the communicationblock; a control interface provided to communicate between the controlblock and the silicon photonics device, the control interfacecomprising: a modulator bias voltage input; a laser DC bias currentinput; a photocurrent or set output; a power monitor current/voltageoutput; a photodetector bias input; a heater current/voltage input; aphotocurrent from input signal or set output; a wavelength monitorvoltage/current/resistance output.
 15. The device of claim 14 whereinthe signal processing block comprises a FEC block, a digital signalprocessing block, a framing block, a protocol block, and a redundancyblock; and the input/output block comprising a SerDes block, a CDRblock, a compensation block, and an equalizer block; wherein theinterface is configured on the silicon photonics device.
 16. The deviceof claim 15 wherein the driver module is selected from a current driveor a voltage driver.
 17. The device of claim 15 wherein the drivermodule is a differential driver.
 18. The device of claim 15 wherein theamplified modulation format is selected from NRZ format or PAM format.19. The device of claim 15 wherein the phase modulation format isselected from BPSK or nPSK.
 20. The device of claim 15 wherein thesignal processing block comprises a FEC block, a digital signalprocessing block, a framing block, a protocol block, and a redundancyblock; wherein the amplified modulation format is a PAM format.
 21. Thedevice of claim 15 wherein the phase/amplitude modulation is QAM. 22.The device of claim 15 wherein the silicon photonic device is configuredto convert the output data into an output transport data in a WDMsignal.
 23. The device of claim 15 wherein the control block isconfigured to initiate a laser bias or a modulator bias.
 24. The deviceof claim 15 wherein the control block is configured for laser bias andpower control of the silicon photonics device.
 25. The device of claim15 wherein the control block is configured with a thermal tuning orcarrier tuning device each of which is configured on the siliconphotonics device.
 26. The device of claim 15 wherein the SerDes block isconfigured to convert a first data stream of N into a second data streamof M.